QTableWidget: assume column 0 when dropping a row below another one

When dropping at a column > 0, the deserialized data wrapped around,
leading to multiple rows being inserted instead of just one (and
column 0 remained empty). Very weird behavior from the user's point of
view.

Drive-by whitespace changes due to clang-format.

Fixes: QTBUG-1387
Change-Id: I8d1dc14c124e468454e98ea6a14f33e3bef6e41a
Reviewed-by: Christian Ehrlicher <ch.ehrlicher@gmx.de>
(cherry picked from commit ff8068deb45e45eb683745486956d3c6c795a708)
Reviewed-by: Qt Cherry-pick Bot <cherrypick_bot@qt-project.org>

src/widgets/itemviews/qtablewidget.cpp

@@ -849,9 +849,12 @@ bool QTableModel::dropMimeData(const QMimeData *data, Qt::DropAction action,
     if (index.isValid()) {
         row = index.row();
         column = index.column();
-    }else if (row == -1 || column == -1) {  // The user dropped outside the table.
+    } else if (row == -1 || column == -1) { // The user dropped outside the table.
         row = rowCount();
         column = 0;
+    } else { // The user dropped between two rows
+        // This means inserting a row, which only makes sense at column 0
+        column = 0;
     }
 
     QTableWidget *view = qobject_cast<QTableWidget*>(QObject::parent());